Pertussis epidemilogy in Argentina, trends over 1969-2012

FLORES DARÍO; FIORI SILVANA; BASILE LAURA; BOTTERO DANIELA; PIANCIOLA LUIS; LARA CLAUDIA; GAILLARD MARÍA EMILIA; GALAS MARCELO; REGUEIRA MABEL; RUGGERI DIEGO; SORHOUET CECILIA; DANIELA HOZBOR

Dublin

Simposio; 10th International Symposium on Bordetella; 2013

Trinity Biomedical Sciencies Institute

In Argentina, the incidence of pertussis has increased steadily since 2002. Here we describe some trends of the disease during 1969-2012 period and discuss the possible causes that could explain the re-emergence of the disease. CDC and the Argentinian Ministry of Health criteria were used for pertussis diagnosis. Mass vaccination against pertussis with a whole cell vaccine was introduced in Argentina 1970 s. In 2010 and 2012, acellular vaccine boosters were implemented for 11-year-old adolescents and pregnant women respectively. During the period 1969-2012, 431,508 patients with symptoms compatible with pertussis were notified. While the largest proportion of cases occurred in children under 6 months and in patients with incomplete immunization schemes to provide protection, there were also many cases in adolescent and adults. Regarding molecular epidemiology, we observed the successive appearance of non-vaccine type alleles for ptxA, prn, ptxP and fim3 after the introduction of vaccination. Based on the allelic variation in the four genes, 6 allele types could be defined. Two of these are typical for vaccine strains used in Argentina and other countries. The other 4-allele types are distinct from the vaccine types. Vaccine-type strains, predominant closed to the introduction of vaccination, were replaced by novel strains. It is noteworthy the emergence of ptxP3 strains related to increased notifications. This asociation, that could explain in part the emergence of the disease, has also been observed in The Netherlands, Finland and Australia.